CBJ Assembly looking into Salmon Creek filtration system

CBJ Enginnering Director Rorie Watt points to the screen during a presentation on the city's water system. (Photo by Casey Kelly/KTOO)

The Juneau Assembly Committee of the Whole last night (Monday) asked the city attorney to draft a resolution conveying its interest in building a filtration system for Salmon Creek – the city’s secondary water supply.

The issue of how Juneau residents get their water has been raised by the Assembly’s ongoing investigation of whether to pursue reopening the old AJ Mine near downtown. The AJ ore body is partly owned by the city, and located in Last Chance Basin – Juneau’s primary source of drinking water.

A Salmon Creek filtration system could open the door to mine development. But Assembly members say it’s too soon to go down that road.

Right now Salmon Creek supplies about a third of Juneau’s water, while most comes from Gold Creek in Last Chance Basin. CBJ Engineering Director Rorie Watt told the Assembly that’s partly because Salmon Creek is not available year round.

“Since Salmon Creek is a surface water source, and is subject to seasonal turbidity, at times we have to take it offline because of the murkiness in the water,” Watt explained. “We could keep it online all the time if we filtered it.”

Watt recently completed a draft report on Juneau’s water system, requested by the Assembly as part of its review of the AJ Mine. The report outlines several scenarios for future development of the system, with and without a gold mine operating in Last Chance Basin.

Watt said one of the more attainable scenarios would involve converting Salmon Creek into a year round supply, while diverting water from the AJ Mine drainage tunnel away from Gold Creek.

“It’s the most neat and tidy,” he said. “It identifies the solution to potential contamination at Gold Creek and it identifies a volume supply increase for losses at Gold Creek.”

Watt said he would expect a mining company to pay for the cost of diverting the AJ drainage tunnel. But the city would have to pursue the Salmon Creek filtration system on its own. He said a facility capable of filtering four million gallons of water per day would meet the city’s current peak usage. Watt estimated a plant that size would cost about $6-million. But a larger facility would allow for growth in water consumption.

“If we were to go down the road of pursuing a filtration plant, there would be a lot of further investigation about which type of filtration plant would be best for Juneau, and there would be a lot of discussion about sizing that plant, and what size would be most appropriate,” said Watt.

Mayor Bruce Botelho suggested a resolution expressing conceptual support for a Salmon Creek filtration system, without identifying a funding source. If the Assembly wishes to pursue it, Botelho said the plant could eventually be added to the city’s long term Capital Improvements Projects list or put to voters as part of a one-percent sales tax measure.

But at this point, the mayor said the resolution would be a way to gauge public support.

“The reason I suggest the resolution is it would create an avenue for the public to specifically comment to us on that proposed course of action,” he said.

Assembly member Karen Crane said sorting out the city’s water supply issues should come before any decision on whether to reopen the AJ.

“We heard, even from many pro-mine people who spoke and gave testimony, that water was also an issue for them,” Crane said. “And I just am not prepared to go any further with anything until we come up with a plan for water.”

Mine or no mine, Botelho said the city should look to improve its water system. He said continuing to have two sources of drinking water – Salmon Creek and Gold Creek – would best serve the public.

“I see it as a confluence of interests, both in terms of community sentiment about having redundancy in our water supply, and it also, I think, coincides with the interests of advancing mining were that to come. But it is in its own way stand alone,” said Botelho.

The draft resolution will come back to the Committee of the Whole and be refined before possibly being moved to the full Assembly.